Digital arthrodesis of the foot is a common surgical procedure for correction of acquired or congenital digital deformities, including, for example, hammertoe, mallet toe deformities, and similarly encountered foot maladies affecting or involving the digits (toes).
Historically, the involved digit(s) and respective joints are corrected via a stepwise reduction using, for example, a specific joint resection arthoplasty, (cutting a small amount of articular cartilage and bone to straighten and maintain flexibility of the involved digit) or a specific joint arthrodesis (fusion or permanent stiffening of the joint in a corrected neutral position). Prior to the creation of the various embodiments disclosed herein, the “gold standard” of affixing and imparting mechanical stability to an intended digital arthrodesis has been the application of a single intramedullary positioned standard sized Kirschner wire (“K-wire”), which is routinely exposed externally to the distal tip of the involved digit. For example, FIG. 1A depicts a K-wire positioned in an affected digit. Many surgeons have employed the K-wire for the express purpose of providing stability to the intended arthrodesis site and/or maintaining, stabilizing, and/or directly reducing concurrent metatarsophalngeal joint contracture associated with digital deformity.
Disadvantages of standard K-wire fixation include the defined requirement of removal, migration, bending, or breaking of the “K-wire,” loss of fixation and/or loss of stability at the intended arthrodesis site, pin tract site irritation, inflammation, pain, and/or development of infection, including deep infection, and the routine external exposure of the K-wire, which is recognized to leave patients and physicians dissatisfied. More specifically, K-wire fixation remains external to the distal aspect of the digit, resulting in a variety of potential problems, including wound complications, limitation of ambulation, and secondary events. Furthermore, following K-wire removal, the potential loss of stability at the intended arthrodesis site can be related to recurrence of deformity, fibrous union, non-union, and pain, as well as failure to gain lasting correction of the deformity.
Newer known intra-medullary devices—solid and cannnulated designs—are commercially available as an alternative fixation device to traditional K-wire fixation, offering completely internal placement. FIG. 1B depicts one embodiment of solid intra-medullary devices. These newer devices are intended to afford a greater degree of intramedullary fixation and stability to the intended arthrodesis site and obviate the need for an exposed intra-medullary fixation device. (i.e. “K-wire” fixation.)
Complications of emerging solid and/or cannulated intramedullary devices are well established, including failure to impart stability, loss of stability, loss of fixation, breakage of device, fracture of adjacent cortical bone, device loosening, osteolysis, handling and storage constraints due to metallurgy properties, inventory control dissatifiers, cost, difficulty in removal, bone loss, secondary procedures, and complications salvaged via explanation, revisional arthrodesis, bone grafting considerations, adjacent digit syndactyly and/or digital amputation. Further, few of the newer intramedullar technologies are compatible and approved (via 510K clearance) to be used concurrently with Kirschner wire fixation.
There is a need in the art for an improved extramedullary device designed specifically for the intended arthrodesis of a digital arthrodesis of the foot or hand.